Add more information to provenance events to facilitate full graph traversal

Although NiFi has a capability in the UI to issue and display lineage queries for provenance events, it is not a complete graph that can be traversed if for example provenance events were stored in a graph database. The following features should be added:

• A reference in a provenance event to any parent events ("previousEventIds")
• Add methods to GraphClientService to generate queries/statements in popular graph languages such as Tinkerpop/Gremlin, Cypher, and SQL
• Add ArcadeDB service as reference implementation for SQL generation